Cell cycle, DNA, and replication - PowerPoint Presentation

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Cell cycle, DNA, and replication

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BIO…

LIFE….

THINK ABOUT THIS:

What do we do in our lifetime?

What are the major stages of our life?

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What are the Major stages of physical development in our lives?

What would it look like

i

f we put this into a pie

c

hart?

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Imagine you are a bacteria:

What are the major stages in your life?

TRY ME:

What is A? B? C?

What is D/E/F/G collectively

called?What is D?What is E?What is F?What is G?

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The life of a cell

Cells have a life cycle just like we do- born, grow, reproduce, and die.

They only spend part of

their life cycle reproducing (M)- mitosis

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Cell Cycle

1. Interphase (G1, S, G2) –

cell grows, prepares to divide (G phases) and DNA replicates (S phase)

2. Mitosis:

nucleus divides; each nuclei winds up with the same # and kind of chromosomes as the parent (P-M-A-T)

3.

Cytokinesis

: division of cytoplasm

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COMING UP IN THIS CLASS…

In the upcoming months, we will be analyzing what happens stages in great detail. Which stage do you think the following upcoming material will focus on?

Topics to cover:

Cell cycle and events

DNA structure and replication?

DNA structure

Cell reproduction (asexual- bacteria)?Cell reproduction (growth- multicellular)?DNA and making proteinsProteins and regulation of the cell cycleWhat happens when things go wrong….

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NUCLEIC ACIDS: The 4

th

category of Biomolecules

What were the 4 macromolecules/biomolecules?

What are monomers? Polymers?

What is the name of the process that builds monomers to polymers called?

What is the reverse process called?

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Nucleic Acids

9

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Nucleic Acids

are the chemical link between generations dating back to the beginning of life on earth.

 

Nucleic Acids

10

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A nucleic acid is a complex macromolecule that stores information in cells in the form of a

code

.

Nucleic Acids

11

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Terminology:

What is the difference and relationship between the following:

DNA -nucleus

Chromosomes - chromatid

Genes - chromatin

Centromere -histones

Nucleotides - telomere12

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WHAT IS THE “STUFF” OF HEREDITY?

WHAT IS ITS STRUCTURE?

The following scientists helped to

answer these questions.

Griffith

AveryHershey-ChaseWatson, Crick

Wilkins and FranklinChargaff

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I. GRIFFITH’S EXPERIMENT 1928

A.

-

make a vaccine against

harmful S.

pneumoniae bacteria 1. virulent S strain (S. pneumoniae)

a. virulent means disease causing b. capsule around the bacteria provides protection from body defenses

2.

non virulent R

strain

(no capsule)

a. destroyed by body(can not cause

disease)

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B.

PROCEDURE and RESULTS

1. mouse injected with R cells

2. mouse injected with S cells

3. mouse injected with heat killed S cells

4. mouse injected with killed S cells mixed with live R cells

mouse lives

mouse dies

mouse lives

mouse dies

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Results of Griffith’s Experiment

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C.

C

- Heat-killed S bacteria release hereditary material that makes R strain bacteria virulent

HOW???

1.

Principle of Transformation a. transfer of genetic material (DNA) from one organism to another b. DNA for making a capsule was transferred from the S strain to the R strain making it virulent

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II.

AVERY’S EXPERIMENTS (early 1940’s)

A

– Is the transforming agent protein, RNA or DNA?

B

.

PROCEDURE – (Three Experiments) 1. destroy 3 different molecules in the heat-killed S strain bacteria and mix with R strain bacteria

a. destroy protein (protease enzyme) b. destroy RNA (RNase enzyme) c. destroy DNA (DNase enzyme)

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C. Results

1. Missing protein

a. transforms R cells to S cells

(mouse dies)

2. Missing RNA

a. transforms R cells to S cells)

(mouse dies)3. Missing DNA a. did not transform R cells to S cells

(mouse lives)

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Oswald Avery

D. Conclusion

– DNA is responsible for

the transforming principle

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III. HERSHEY-CHASE EXPERIMENT

1952 (Martha Chase and Alfred Hershey)

– Is the hereditary material in viruses protein or DNA?

B.

PROCEDURE

1. Label protein and DNA in a phage with radioactive isotopes (S-35 and P-32)

a. a phage is a virus that attacks bacteria b. S-35 labels protein and P-32 labels DNA

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Martha Chase and Alfred Hershey used

Phage Viruses for Their Experiment

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B. Procedure

2. Allow protein-labeled and DNA-

labeled phage (virus) to infect

E. coli

bacteria

3. remove and separate phage (virus) from the bacteria (E. coli)

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Hershey-Chase Experiment

all viral DNA and a small amount of protein entered the bacteria

D.

CONCLUSION

-

DNA is the hereditary molecule in viruses

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IV. Watson and Crick (1953) /Wilkins and Franklin

A. Watson and Crick

1. double helix model of DNA based on the

work of other scientists

B. Maurice Wilkins and Rosalind Franklin

1. x-ray diffraction photographs of DNA

helped Watson and Crick develop their model 2. Watson, Crick and Wilkins received Nobel Prize in l962 (Franklin died in 1958

and could not be named for the award)

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X-ray Diffraction Photo Rosalind Franklin

of DNA) and Maurice Wilkens

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DNA Double Helix Watson and Crick

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What are chromosomes???

29

Nucleotides

make up

DNA

DNA winds into Chromatin

Chromatin condenses into Chromosomes are composed of chromatids held together at the centromereChromosomes contain GenesGenes are sections of

DNA

DNA

is made of

nucleotides

Chromosomes contain

Instructions for making

YOU!!!

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Chromosome - DNA

Chromosome- Chromatid

Where is it located in the cell? NUCLEUS!

How is it arranged?

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Figure 9-4 Chromosome structure

DNA double helix

histone proteins

DNA wound

around histone

proteins

Loops attached

to a protein scaffold;

this stage of partial

condensation typically

occurs in a nondividing

cell

Coiled DNA/histone beads

protein scaffold

Folded

chromosome,

fully condensed

in a dividing cell

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NUCLEIC ACID

What is the monomer of nucleic acids called?

What components does it have?

What are the 2 major nucleic acids?

What do they do?

What ways are they similar in structure?What 3 ways do they differ in structure?

THEME….how is the structure related to their function?33

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MONOMER: Nucleic acids are made of long chains of

nucleotides

.

 

Nucleotides are made of three components:

1. sugar

2. phosphate group 3. nitrogen base

Nucleic Acids

34

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Examples of nucleic acids are :

1. DNA

2. RNA

Nucleic Acids

35

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DNA =

deoxyribonucleic acid

 

its components are:

1.

deoxyribose

(sugar)

2. phosphate group 3. nitrogen base

DNA

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Purpose? To code for everything in your body...genetic blueprint!

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The Components and Structure of DNA

There are four kinds of bases in in DNA:

adenine

guanine

cytosine

thymine

37

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Adenine (A) – Thymine (T)

Guanine (G) – Cytosine (C)

A and G are purines (

AG

gies

eat

Purina)C and T are pyrimidines

DNA38

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DNA

 

The paired nitrogen bases formed

two

long strands of nucleotides that compliment each other.

39

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Nitrogen Bases

are connected

between

sugars

and

phosphates

They declared, “This structure is a “double helix”

The structure is antiparallel (upsidedown).This causes a problem in replicationBecause replication is a one way

d

irection.

DNA

40

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DNA Double Helix

41

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DNA forms

chromosomes

, units of genetic information which pass from parent to offspring.

DNA

 

                      

DNA is wound into structures called chromosomes during cell

division

42

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If you unraveled all your chromosomes from all of your cells and laid out the DNA end to end, the strands would stretch from the Earth to the Moon about

6,000 times

.

 

               

DNA

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RNA has a different

sugar

than DNA

RNA =

ribonucleic acid

It’s components are :

1. ribose (sugar)

2. phosphate group 3. nitrogen baseRNA

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It also has different bases than DNA

adenine ---

uracil

cytosine

--- guanine

 

RNA is also single

stranded, not double stranded like DNA.

RNA

45

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Review

DNA

RNA

-

Double

stranded

- Single stranded- Sugar =

deoxyribose- Sugar = ribose- Adenine pairs with Thymine- Adenine pairs with Uracil

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DNA Replication

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I. Why Must DNA Replicate? 

Every time a cell divides, it must first make a copy of it’s

chromosomes

.

Therefore, each cell

can have a

complete set

of chromosomes.

DNA Replication

48

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Without replication, species could not survive and individuals could not successfully grow and

reproduce

.

DNA Replication

49

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II. How DNA Replicates

DNA is a molecule composed of

TWO

strands, each consisting of a sequence of

nucleotides

.

The order of the

nitrogen bases on one strand mandates the sequence of bases on the complementary strand.

DNA Replication

50

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If you know the bases on one strand, you can predict which bases will occur on the complementary strand.

A -----

G -----

T -----

C -----

C -----

C -----

T -----

During Replication each strand serves as a

template

to create a new strand.

DNA Replication

T

C

A

G

G

G

A

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III. Steps In Replication

1)

Helicase

break down the

hydrogen

bonds between the two DNA strands, unzipping the molecule

Steps in Replication

52

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DNA Replication

1.

Helicase

break the hydrogen bonds between the bases so the chains of DNA can separate or unwind

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2) As the DNA unzips,

SSB (single strand binding protein holds the strands down.

3)

Primase

(RNA) makes start platforms

Steps in Replication

54

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4)

DNA polymerase adds nucleotides (from surroundings in the nucleus) bond to the single strands by

base pairing

(A-T, G-C)

SEMI- CONSERVATIVE REPLICATION:

** The result of this process is the formation of TWO DNA molecules, each

identical to the original molecule- with one old strand and one new strand.

Steps in Replication

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DNA Replication

56

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2. Other enzymes add

new nucleotides,

which form new

hydrogen bonds

with their

complimentary

nucleotide.Red = original strandBlue = new strand

DNA Replication

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DNA Replication

Results in 2 semi-conservative double stranded molecules

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WHAT IS THE ROLE OF:

Helicase-

SSB-

Replication fork-

DNA

Polymerase-

Ligase-

Leading strand-

Lagging strand-

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ANIMATIONS OF DNA REPLICATION

http://

www.bioteach.ubc.ca/TeachingResources/MolecularBiology/DNAReplication.swf

http://

www.mcb.harvard.edu/Losick/images/TromboneFINALd.swf

http://highered.mcgraw-hill.com/sites/0072556781/student_view0/chapter11/animation_quiz_2.html

http://www.sinauer.com/cooper/4e/animations0601.html

AMEOBA SISTERS:https://

www.youtube.com/watch?v=5qSrmeiWsuc&index=1&list=PLwL0Myd7Dk1F1pp-DaLx3ygO_7xA-yyd4

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1.

What are the two types of nucleic acids?

2

. What are the three components of a nucleotide?

3.

What are the similarities between DNA and RNA? What are the differences?

4. Describe the process of DNA replication.5. Why does a DNA molecule undergo replication?

Reflect and Review62